In the related art, for casting mold materials used for casting steel materials and the like, there is a demand for excellent characteristics such as high-temperature strength enabling the casting mold materials to withstand strong thermal stress, high-temperature elongation enabling the casting mold materials to withstand severe thermal fatigue environments, and wear resistance (hardness) at a high temperature. Therefore, Cu—Cr—Zr-based alloys being favorable in terms of the above-described characteristics are used as continuous casting mold materials. For example, Japanese Unexamined Patent Application, First Publication No. H05-339688 discloses a casting mold material containing 0.3% to 1.2% of Cr, 0.05% to 0.25% of Zr, and a balance consisting of Cu and impurities.
In addition, it is known that, in Cu—Cr—Zr alloys, the above-described characteristics are improved by further adding additive elements, and, for example, Japanese Unexamined Patent Application, First Publication No. H04-028837 discloses a casting mold material containing, in addition to Cr and Zr, 0.005% to 0.7% of Ti and 0.003% to 0.1% of Si and further containing 0.005% to 1.5% of one or more of Fe, Ni, and Co and a balance consisting of Cu and impurities.
In the Cu—Cr—Zr-based alloys described in Japanese Unexamined Patent Application, First Publication No. H05-339688 and Japanese Unexamined Patent Application, First Publication No. H04-028837, when a supersaturated solid solution of Cr and Zr which turns into a non-equilibrium phase by a solution treatment is formed, and Cr and Zr are dispersed and precipitated by the subsequent aging treatment, mechanical characteristics such as high-temperature strength, high-temperature elongation, and the wear resistance (hardness), the electrical conductivity, and the thermal conductivity are improved. In order to form the above-described supersaturated solid solution, it is necessary to carry out rapid cooling after the solution treatment.